I know parents are very busy and totally understand this may not be an option for your family If this is the case I have included a video that your child could watch instead completing the experiment ID: 1043176
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1. This lesson contains a science experiment- you will be asked to melt chocolate, make observations and time how long it takes for the chocolate to melt under different circumstances. I know parents are very busy and totally understand this may not be an option for your family.If this is the case- I have included a video that your child could watch instead completing the experiment.
2. 29th January 2021L.O: To know if temperature can affect the state of a material
3. Big Question:What causes a material to change state?During this lesson we are going to focus on this line of enquiry: Does temperature affect the state of a material?
4. What MakesMaterials Change State?Materials can be in three different states: solid, liquid or gas.But how do materials change state?Have a look at the diagram opposite and choose the correct labels for each arrow.solidliquidfreezingmelting
5. What MakesMaterials Change State?When a solid turns into a liquid it is called melting.The temperature at which a solid material melts is called itsmelting point. Different materials have different melting points.If a solid material is heated to its melting point, it will start tomelt and will change state from a solid to a liquid.In a solid, the particles are closely packed together and are vibratingon the spot. When a solid is heated, the particles start to move faster and faster. If enough heat is applied, the particles will have enough energy to move about. They are still close together, but can move over and around each other. At this point, the solid has melted to form a liquid.
6. What MakesMaterials Change State?When a liquid turns into a solid it is called freezing.The temperature at which a liquid material freezes is called itsfreezing point. Different materials have different freezing points.It is important to remember that some materials have freezingpoints above 0°C. For example, the freezing point of iron isaround 1550°C! Interestingly, this means its melting point is alsoits freezing point, just in reverse! Above this temperature, it will beliquid iron. Below this temperature, it will be solid iron.If a liquid material is cooled to its freezing point, it will turn from aliquid to a solid.The particles in a liquid are close together, but can move quite quickly around and over each other. As it is cooled, the particles start to slow down. Eventually, they slow down so much that they only move gently on the spot, and a solid structure is formed. The material has frozen.
7. What MakesMaterials Change State?
8. Melting and Freezing PointsFor most materials, their melting and freezing points are the same. Although it sounds strange, think of the melting and freezing point as a barrier. If the material is heated to a temperature higher than this, it will melt. If the material is cooled to a temperature lower than this, it will freeze. 0°C Freezing point of water.0°C Melting point of ice.
9. Melting PointswaxCan you match these materials with theirapproximate freezing and melting points?aluminium35°C660°Cbuttersilver50°C0°Cgoldice cream1060°C960°C
10. Melting PointswaxHow did you do? Why would it be useful for someone toknow the freezing and melting points of these materials?aluminium35°C660°Cbuttersilver50°C0°Cgoldice cream1060°C960°C
11. Well hello again Year 4…It’s me, Susan! Susan the Scientist.I think I’m just in time to interrupt your lesson and ask for your help…I hear you’ve been learning all about materials. Well, I need help with one specific material…chocolate. Firstly, is chocolate a solid, a liquid or a gas? Can it change state?
12. You see, I’ve been asked to help prepare some tasty treats for Nosey Norman’s birthday and …I’ve been so busy, I’ve left it to the last minute.I’m now just getting the food ready for his birthday party, and I want to make some chocolate crispy cakes. They’re Nosey Normans favourite! His party is only a few hours away, so I need to make them fast! Can you help me? What information do I need to know if I am wanting to make chocolate crispy cakes…quickly?
13. Well then Year 4, can we stop and help Susan? If Susan is making chocolate crispy cakes…what information does she need to know?Firstly, how do you make chocolate crispy cakes?Can chocolate change state?
14. So, we know chocolate needs to be melted in order to make crispy cakes. Therefore, we know chocolate can change state.Take a look at this chocolate bar …What state is it?What will help when it is melted?So, in order to make crispy cakes quickly- Susan needs to know the best temperature for melting chocolate.
15. Guys, I’ve got an idea to find out the best and quickest way to melt chocolate. Do you think you could complete the experiment for me?You will place a piece of chocolate in a foil tin and float each tin on a different temperature of water.You will see how long it takes for the pieces of chocolate to melt at the different temperatures.
16. At this stage, if you are able to complete the experiment and melt the chocolate under different circumstances- amazing.If not, you can watch this video where they complete a slightly different experiment- and melt three different types of chocolate. https://www.youtube.com/watch?v=Cx5nTBmTpEc
17. Remember, when we are carrying out an experiment or investigation, we must include all of the following: Aim (What are you trying to find out?)Hypothesis (Prediction) VariablesI am going to changeI am going to measureMy test is a fair test becauseEquipment list MethodResults Conclusion
18. Aim (What are you trying to find out?)The aim of my investigation is to find out the best temperature to melt chocolate in the quickest timeHypothesis (Prediction) I predict the chocolate placed onto the tin case in the hottest water will melt the quickest because chocolate melts when it is hot
19. VariablesI am going to change the temperature I am going to measure the time it takes for the chocolate to melt My test is a fair test because I will use the same brand and type of chocolate, the same brand and type of tin case and I am only changing one variable
20. Equipment listChocolateTrayHot waterCold waterWater from the hot tapThermometerFoil cases
21. PredictionI predict the chocolate placed in the hottest water will melt in the quickest time because solids change shape when heat is applied.
22. MethodPour the three different jugs of water into each trayRecord the temperature of the water in each tray Carefully place a tin case on top of the water in each trayPlace one square of chocolate onto each tin caseBegin the timerRecord the time it takes for each chocolate square to melt
23. Tray 1Tray 2Tray 3Temperature of the waterTime taken for the chocolate to melt Results:
24. Can you present your data in a graph?
25. A bar chart to show time taken for a chocolate square to melt Time (in seconds and minutes)Temperature of the water
26. ConclusionAfter completing this experiment, I would recommend Susan placed her chocolate mixture on the hottest temperature because the hotter the water, the quicker the chocolate will melt.
27. I want to make sure thechocolate crispy cakes are solid before my party guests arrive! I am going to put them outside so the chocolate freezes and changes into a solid quicker.Do you think Susan's idea is a good one? Why?