Have a look at these for ideas to try at home:

https://www.bbc.co.uk/bitesize/subjects/zb9d7ty - KS1 Bitesize DT

https://www.bbc.co.uk/bitesize/subjects/zyr9wmn - KS2 Bitesize DT

https://www.exploratorium.edu/pie/ideas.html#page - They have an idea library that shows models that could be made

http://www.foodafactoflife.org.uk/ - Lots of Food Technology information

http://www.howstuffworks.com - Some good ideas

https://www.lego.com/en-gb/themes/letsbuildtogether/365-activities​ - Links to Lego building