User DrZ214

20 votes

3 answers

5k views

What type of abrasive grit was used to grind lenses for telescopes?

asked Jan 10, 2023 at 21:50

11 votes

1 answer

461 views

A knot cannot be tied in 4-dimensions, but when was this conjectured and proven?

asked Feb 19, 2017 at 4:40

6 votes

1 answer

985 views

Before the discovery of the neutron, how did scientists explain standard atomic weights?

asked Oct 14, 2017 at 2:56

5 votes

0 answers

176 views

Why was Beaumont's steam engine not replicated for about 100 years?

asked Jun 7, 2018 at 18:18

5 votes

1 answer

559 views

When William Herschel discovered Uranus, who else at the time had a comparable telescope?

asked Feb 28, 2017 at 2:34

5 votes

1 answer

774 views

Why was the V-2 not a solid rocket, and/or what is the scientific history of solid rockets?

asked Aug 14, 2015 at 22:25

5 votes

1 answer

2k views

How did chemists figure out atomic weights, when hydrogen, etc., were first discovered?

asked Feb 5, 2016 at 7:41

4 votes

2 answers

408 views

What were the applications of ellipses before elliptical orbits were discovered?

asked Jan 29, 2016 at 1:18

4 votes

0 answers

269 views

When was the British Flag Theorem discovered or proven?

asked Apr 2, 2017 at 23:24

4 votes

1 answer

109 views

What/When was the first radio nav system capable of triangulating your position?

asked Sep 29, 2017 at 20:38

2 votes

1 answer

6k views

When was double-paned glass first invented and used for insulation?

asked Oct 25, 2017 at 5:34

1 vote

0 answers

90 views

In the old days, how did chemists trap and measure gases?

asked Sep 17, 2018 at 19:13

0 votes

2 answers

1k views

When did Europe start accurately predicting solar and lunar eclipses? [duplicate]

asked Apr 21, 2016 at 1:09

-1 votes

1 answer

160 views

How did crude oil pipelines work before WW2?

asked Oct 17, 2017 at 2:20

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14 Questions

What type of abrasive grit was used to grind lenses for telescopes?

A knot cannot be tied in 4-dimensions, but when was this conjectured and proven?

Before the discovery of the neutron, how did scientists explain standard atomic weights?

Why was Beaumont's steam engine not replicated for about 100 years?

When William Herschel discovered Uranus, who else at the time had a comparable telescope?

Why was the V-2 not a solid rocket, and/or what is the scientific history of solid rockets?

How did chemists figure out atomic weights, when hydrogen, etc., were first discovered?

What were the applications of ellipses before elliptical orbits were discovered?

When was the British Flag Theorem discovered or proven?

What/When was the first radio nav system capable of triangulating your position?

When was double-paned glass first invented and used for insulation?

In the old days, how did chemists trap and measure gases?

When did Europe start accurately predicting solar and lunar eclipses? [duplicate]

How did crude oil pipelines work before WW2?